package com.test.ddaidai.gesture;

import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;


public class RSACoder {
	//非对称密钥算法  
    public static final String KEY_ALGORITHM="RSA";  
    /** 
     * 密钥长度，DH算法的默认密钥长度是1024 
     * 密钥长度必须是64的倍数，在512到65536位之间 
     * */  
    private static final int KEY_SIZE=512;  
    //公钥  
    private static final String PUBLIC_KEY="xiaoxiaorenzhe";  
      
    //私钥  
    private static final String PRIVATE_KEY="dadapangzi";  
    
    /** 
     * 初始化密钥对 
     * @return Map 甲方密钥的Map 
     * */  
    public static Map<String,Object> initKey() throws Exception{  
        //实例化密钥生成器  
        KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance(KEY_ALGORITHM);  
        //初始化密钥生成器  
        keyPairGenerator.initialize(KEY_SIZE);  
        //生成密钥对  
        KeyPair keyPair=keyPairGenerator.generateKeyPair(); 
        //甲方公钥  
        RSAPublicKey publicKey=(RSAPublicKey) keyPair.getPublic();  
        System.out.println("系数："+publicKey.getModulus()+"  加密指数："+publicKey.getPublicExponent());
        //甲方私钥  
        RSAPrivateKey privateKey=(RSAPrivateKey) keyPair.getPrivate(); 
        System.out.println("系数："+privateKey.getModulus()+"解密指数："+privateKey.getPrivateExponent());
        //将密钥存储在map中  
        Map<String,Object> keyMap=new HashMap<String,Object>();  
        keyMap.put(PUBLIC_KEY, publicKey);  
        keyMap.put(PRIVATE_KEY, privateKey);  
        return keyMap;  
          
    }  
    
    /** 
     * 私钥加密 
     * @param data待加密数据 
     * @param key 密钥 
     * @return byte[] 加密数据 
     * */  
    public static byte[] encryptByPrivateKey(byte[] data,byte[] key) throws Exception{  
          
        //取得私钥  
        PKCS8EncodedKeySpec pkcs8KeySpec=new PKCS8EncodedKeySpec(key);  
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);  
        //生成私钥  
        PrivateKey privateKey=keyFactory.generatePrivate(pkcs8KeySpec);  
        //数据加密  
        Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);  
        return cipher.doFinal(data);  
    }  
    
    /** 
     * 公钥加密 
     * @param data待加密数据 
     * @param key 密钥 
     * @return byte[] 加密数据 
     * */  
    public static byte[] encryptByPublicKey(byte[] data,byte[] key) throws Exception{  
          
        //实例化密钥工厂  
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);  
        //初始化公钥  
        //密钥材料转换  
        X509EncodedKeySpec x509KeySpec=new X509EncodedKeySpec(key);  
        //产生公钥  
        PublicKey pubKey=keyFactory.generatePublic(x509KeySpec);  
          
        //数据加密  
        Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);  
        return cipher.doFinal(data);  
    }  
    /** 
     * 私钥解密 
     * @param data 待解密数据 
     * @param key 密钥 
     * @return byte[] 解密数据 
     * */  
    public static byte[] decryptByPrivateKey(byte[] data,byte[] key) throws Exception{  
        //取得私钥  
        PKCS8EncodedKeySpec pkcs8KeySpec=new PKCS8EncodedKeySpec(key);  
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);  
        //生成私钥  
        PrivateKey privateKey=keyFactory.generatePrivate(pkcs8KeySpec);  
        //数据解密  
        Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.DECRYPT_MODE, privateKey);  
        return cipher.doFinal(data);  
    }  
    
    /** 
     * 公钥解密 
     * @param data 待解密数据 
     * @param key 密钥 
     * @return byte[] 解密数据 
     * */  
    public static byte[] decryptByPublicKey(byte[] data,byte[] key) throws Exception{  
          
        //实例化密钥工厂  
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);  
        //初始化公钥  
        //密钥材料转换  
        X509EncodedKeySpec x509KeySpec=new X509EncodedKeySpec(key);  
        //产生公钥  
        PublicKey pubKey=keyFactory.generatePublic(x509KeySpec);  
        //数据解密  
        Cipher cipher=Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.DECRYPT_MODE, pubKey);  
        return cipher.doFinal(data);  
    }  
    
    /** 
     * 取得私钥 
     * @param keyMap 密钥map 
     * @return byte[] 私钥 
     * */  
    public static byte[] getPrivateKey(Map<String,Object> keyMap){  
        Key key=(Key)keyMap.get(PRIVATE_KEY);  
        return key.getEncoded();  
    }  
    /** 
     * 取得公钥 
     * @param keyMap 密钥map 
     * @return byte[] 公钥 
     * */  
    public static byte[] getPublicKey(Map<String,Object> keyMap) throws Exception{  
        Key key=(Key) keyMap.get(PUBLIC_KEY); 
        return key.getEncoded();  
    }  
    /** 
     * @param args 
     * @throws Exception  
     */  
    public static void main(String[] args) throws Exception {  
        //初始化密钥  
        //生成密钥对  
        Map<String,Object> keyMap=RSACoder.initKey();  
        //公钥  
        byte[] publicKey=RSACoder.getPublicKey(keyMap);
        //byte[] publicKey = b;
        //私钥  
        byte[] privateKey=RSACoder.getPrivateKey(keyMap);
        System.out.println("公钥："+Base64.encodeBase64String(publicKey)); 
        System.out.println("公钥："+publicKey.length);  
        System.out.println("私钥："+Base64.encodeBase64String(privateKey));  
          
        System.out.println("================密钥对构造完毕,甲方将公钥公布给乙方，开始进行加密数据的传输=============");  
        String str="aattaggcctegthththfef/aat.mp4";  
        System.out.println("===========甲方向乙方发送加密数据==============");  
        System.out.println("原文:"+str);  
        //甲方进行数据的加密  
        byte[] code1=RSACoder.encryptByPublicKey(str.getBytes(), publicKey);
        System.out.println("加密后的数据："+Base64.encodeBase64String(code1));  
        /*System.out.println("===========乙方使用甲方提供的公钥对数据进行解密==============");  
        //乙方进行数据的解密  
        //byte[] decode1=RSACoder.decryptByPublicKey(code1, publicKey);  
        byte[] decode1=RSACoder.decryptByPrivateKey(code1, privateKey);  
        System.out.println("乙方解密后的数据："+new String(decode1)+"");  
          
        System.out.println("===========反向进行操作，乙方向甲方发送数据==============");  
          
        str="乙方向甲方发送数据RSA算法";  
          
        System.out.println("原文:"+str);  
          
        //乙方使用公钥对数据进行加密  
        byte[] code2=RSACoder.encryptByPublicKey(str.getBytes(), publicKey);  
        System.out.println("===========乙方使用公钥对数据进行加密==============");  
        System.out.println("加密后的数据："+Base64.encodeBase64String(code2));  
          
        System.out.println("=============乙方将数据传送给甲方======================");  
        System.out.println("===========甲方使用私钥对数据进行解密==============");  
          
        //甲方使用私钥对数据进行解密  
        byte[] decode2=RSACoder.decryptByPrivateKey(code2, privateKey);  
          
        System.out.println("甲方解密后的数据："+new String(decode2)); /* */
        
        
    }  
}
